In the steps for manufacturing semiconductors there are various steps such as: a back grinding step in which a rear surface of a semiconductor wafer (hereinafter simply referred to as a “wafer”) is ground to miniaturize a semiconductor chip (hereinafter simply referred to as a “chip”); a dicing step in which the wafer having formed thereon a circuit is diced into respective semiconductor chips; a die bonding step in which those formed into chips are bonded to electrode portions of a surface mounting substrate having a wiring pattern thereon; and so forth.
The wafer that has been made ultrathin in the back grinding step is likely to be damaged by even the slightest shocks. Therefore, in order to prevent the wafer that has been made ultrathin from being damaged, at the time of transporting or machining, through warping by a self weight, acceleration, or processing stresses, there has been proposed a fixing jig which supports and fixes the wafer and which is made up of a plate-like jig main body, and a close contact layer which is provided on one surface of the jig main body and which detachably holds the work in close contact (see, e.g., patent document 1). This jig main body has on one surface a plurality of supporting projections which support thereon the close contact layer and also has, along an outer peripheral portion of said one surface, a side wall of substantially the same height as the supporting projections. The close contact layer is adhered to an end surface of the side wall. Between the close contact layer and the jig main body, there is defined a partitioned space which is enclosed by the side wall. The jig main body has formed therein a ventilation hole which is in communication with the partitioned sp ace.
As long as the wafer is held in close contact with this fixing jig, the wafer is held without a positional deviation and damages thereto. On the other hand, when the air within the partitioned space is sucked by evacuation of the ventilation hole, the close contact layer is deformed so as to be dented at the position between the respective supporting projections, and the area of contact of the wafer with the close contact layer will decrease. As a result, the wafer can be removed from the fixing jig without applying a further undue force to the wafer.
Due to the above advantages of the fixing jig, it is proposed: to prepare a protecting structural body for the wafer in which, by fixing the wafer in close contact with the fixing jig, the wafer and the fixing jig are integrated; and to perform the back grinding step and the like or to transport the wafer to the subsequent step in a state of maintaining this protecting structural body.    Patent Document 1: JP-A-2006-216775